Diegetic Sound

In Casablanca, the use of diegetic sound is seen in the restaurant where the woman is performing the guitar and singing and the male is playing the piano for Ilsa. This sound that the actors can hear adds more depth to the film as it can represent the characters and remind us (the audience) of what we connect the song with to the characters.

Non-Diegetic Sound

In Casablanca, non-diegetic sound is used throughout the play with the Classical Casablanca song that is played a few times. It shows the development of the narrative but also the characters as its played in different scenes and each time its played the scene and plot and characters have changed.